Conventionally, a fuel injection valve that starts and stops fuel injection out of an injection hole by using magnetic attraction force generated by energizing a coil is put into practice. In this kind of fuel injection valve, when the coil, for example, is energized, a magnetic attraction force is generated between a fixed core and a moving core. A valve member is integrated with the moving core, and the magnetic attraction force moves the valve member and the moving core in an axial direction. The moving core and the valve member collides with the fixed core not to move further, and a position of the valve member when the fuel injection is performed is determined by an arrangement of the fixed core. In this case, the moving core, which is integrated with the valve member, collides with the fixed core, so that the moving core rebounds apart from the fixed core due to an impact of the collision. Thus, the fuel injection lags behind the energization of the coil, and a responsivity of the fuel injection valve becomes worse. As a result, it becomes difficult to control an injection quantity of the fuel injected out of the injection hole with high accuracy.
In this regard, U.S. Pat. Nos. 6,161,813, 6,279,873, 6,367,769 and their counterparts JP-2000-509787-A, JP-2002-506502-A, JP-2002-528672-A disclose a fuel injection valve having a construction in which the valve member is formed separately from the moving core.
As disclosed in the above-listed documents, when the valve body is formed separately from the moving core, an elastic member is necessary to push one of the valve member and the moving core onto the other so as to move the valve member together with the moving core. If the elastic member is deformed not in an axial direction in which the elastic member generates its restoring force, a magnitude of the restoring force is deviated from standard restoring force. Thus, a guide for preventing the elastic member from being inclined and bent with respect to the axial direction of the elastic member is necessary. However, when a member for the guide is added, the number of parts and assembly processes of the fuel injection valve are increased.